From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 7AA766B0099 for ; Tue, 16 Dec 2008 21:25:25 -0500 (EST) Date: Wed, 17 Dec 2008 11:26:08 +0900 From: Daisuke Nishimura Subject: Re: [PATCH 1/9] fix error path of mem_cgroup_create and refnct handling Message-Id: <20081217112608.c2a88905.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20081216181041.bbe9bc20.kamezawa.hiroyu@jp.fujitsu.com> References: <20081216180936.d6b65abf.kamezawa.hiroyu@jp.fujitsu.com> <20081216181041.bbe9bc20.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "menage@google.com" , "balbir@linux.vnet.ibm.com" , "lizf@cn.fujitsu.com" , nishimura@mxp.nes.nec.co.jp List-ID: On Tue, 16 Dec 2008 18:10:41 +0900, KAMEZAWA Hiroyuki wrote: > > From: KAMEZAWA Hiroyuki > > 1. Fix double-free BUG in error route of mem_cgroup_create(). > mem_cgroup_free() itself frees per-zone-info. > 2. Making refcnt of memcg simple. > Add 1 refcnt at creation and call free when refcnt goes down to 0. > I like this change. > Singed-off-by: KAMEZAWA Hiroyuki Reviewed-by: Daisuke Nishimura Thanks, Daisuke Nishimura. > --- > Index: mmotm-2.6.28-Dec15/mm/memcontrol.c > =================================================================== > --- mmotm-2.6.28-Dec15.orig/mm/memcontrol.c > +++ mmotm-2.6.28-Dec15/mm/memcontrol.c > @@ -2087,14 +2087,10 @@ static struct mem_cgroup *mem_cgroup_all > * Removal of cgroup itself succeeds regardless of refs from swap. > */ > > -static void mem_cgroup_free(struct mem_cgroup *mem) > +static void __mem_cgroup_free(struct mem_cgroup *mem) > { > int node; > > - if (atomic_read(&mem->refcnt) > 0) > - return; > - > - > for_each_node_state(node, N_POSSIBLE) > free_mem_cgroup_per_zone_info(mem, node); > > @@ -2111,11 +2107,8 @@ static void mem_cgroup_get(struct mem_cg > > static void mem_cgroup_put(struct mem_cgroup *mem) > { > - if (atomic_dec_and_test(&mem->refcnt)) { > - if (!mem->obsolete) > - return; > - mem_cgroup_free(mem); > - } > + if (atomic_dec_and_test(&mem->refcnt)) > + __mem_cgroup_free(mem); > } > > > @@ -2165,12 +2158,10 @@ mem_cgroup_create(struct cgroup_subsys * > > if (parent) > mem->swappiness = get_swappiness(parent); > - > + atomic_set(&mem->refcnt, 1); > return &mem->css; > free_out: > - for_each_node_state(node, N_POSSIBLE) > - free_mem_cgroup_per_zone_info(mem, node); > - mem_cgroup_free(mem); > + __mem_cgroup_free(mem); > return ERR_PTR(-ENOMEM); > } > > @@ -2185,7 +2176,7 @@ static void mem_cgroup_pre_destroy(struc > static void mem_cgroup_destroy(struct cgroup_subsys *ss, > struct cgroup *cont) > { > - mem_cgroup_free(mem_cgroup_from_cont(cont)); > + mem_cgroup_put(mem_cgroup_from_cont(cont)); > } > > static int mem_cgroup_populate(struct cgroup_subsys *ss, > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org